$OpenBSD: README-server,v 1.22 2017/05/23 14:17:00 sthen Exp $

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At least two different accounts are involved when working with PostgreSQL:
One is an OpenBSD userid, '_postgresql', which is used as the userid of files
that are part of PostgreSQL.  The other, usually named 'postgres', is not an
OpenBSD userid, i.e. you will not find it in /etc/passwd, but an account
internal to the database system.  The 'postgres' account is called the dba
account (database administrator) and is created when a new database is
initialized using the initdb command.

If you are installing PostgreSQL for the first time, you have to create
a default database first.  In the following example we install a database
in /var/postgresql/data with a dba account 'postgres' and md5 authentication.
We will be prompted for a password to protect the dba account:

       # su - _postgresql
       $ mkdir /var/postgresql/data
       $ initdb -D /var/postgresql/data -U postgres -A md5 -W

Please note that by default the cluster's encoding will be SQL_ASCII. If
you want to have another default encoding, use the option -E with initdb:

       $ initdb -D /var/postgresql/data -U postgres -E UTF8 -A md5 -W

If your cluster is already created, you can specify another encoding when
you create a new database with this command:
	CREATE DATABASE xxx TEMPLATE template0 ENCODING 'xxx' ;

It is strongly advised that you do not work with the postgres dba account
other than creating more users and/or databases or for administrative tasks.
Use the PostgreSQL permission system to make sure that a database is only
accessed by programs/users that have the right to do so.

Please consult the PostgreSQL website for more information, especially when
you are upgrading an existing database installation.


Network Connections
===================
To allow connections over TCP (and other options) edit the file:

	/var/postgresql/data/postgresql.conf

and also edit the pg_hba.conf (in the same directory) making the
appropriate changes to allow connection from your network.

To allow SSL connections, edit postgresql.conf and enable the
'ssl' keyword, and create keys and certificates:

       # su - _postgresql
       $ cd /var/postgresql/data
       $ umask 077
       $ openssl genrsa -out server.key 2048
       $ openssl req -new -key server.key -out server.csr

Either take the CSR to a Certifying Authority (CA) to sign your
certificate, or self-sign it:

       $ openssl x509 -req -days 365 -in server.csr \
         -signkey server.key -out server.crt

Restart PostgreSQL to allow these changes to take effect.

Tuning for busy servers
=======================
The default sizes in the GENERIC kernel for SysV semaphores are only
just large enough for a database with the default configuration
(max_connections 40) if no other running processes use semaphores.
In other cases you will need to increase the limits. Adding the
following in /etc/sysctl.conf will be reasonable for many systems:

	kern.seminfo.semmni=60
	kern.seminfo.semmns=1024

To serve a large number of connections (>250), you may need higher
values for the above.

You may also want to tune the max_connect value in the
postgresql.conf file to increase the number of connections to the
backend.

By default, the _postgresql user, and so the postmaster and backend
processes run in the login(1) class of "daemon". On a busy server,
it may be advisable to put the _postgresql user and processes in
their own login(1) class with tuned resources, such as more open
file descriptors (used for network connections as well as files),
possibly more memory, etc.

For example, add this to the login.conf(5) file:

	postgresql:\
		:openfiles=768:\
		:tc=daemon:

Rebuild the login.conf.db file if necessary:

	# [ -f /etc/login.conf.db ] && cap_mkdb /etc/login.conf

For more than about 250 connections, these numbers should be
increased. Please report any changes and experiences to the package
maintainers so that we can update this file for future versions.

Upgrade Howto (for a major upgrade)
===================================
If you didn't install PostgreSQL by following this README,
you must adapt these instructions to your setup.

Option 1: Dump and Restore
--------------------------

This will work for any upgrade from any major version of PostgreSQL
to the current version.

1) Backup all your data:
# su _postgresql -c "pg_dumpall -U postgres > /var/postgresql/full.sqldump"

2) Shutdown the server:
# rcctl stop postgresql

3) Upgrade your PostgreSQL package with pkg_add.
# pkg_add -ui postgresql-server

4) Backup your old data directory:
# mv /var/postgresql/data /var/postgresql/data-${PREV_MAJOR}

5) Create a new data directory (using -E UTF8 if appropriate):
# su _postgresql -c "mkdir /var/postgresql/data"
# su _postgresql -c "initdb -D /var/postgresql/data -U postgres -A md5 -W"

6) Restore your old pg_hba.conf and (if used) SSL certificates
# su _postgresql -c \
    "cp /var/postgresql/data-${PREV_MAJOR}/pg_hba.conf /var/postgresql/data/"
# su _postgresql -c \
    "cp /var/postgresql/data-${PREV_MAJOR}/server.{crt,key} /var/postgresql/data/"

Some postgresql.conf settings changed or disappeared in this version.
Examine your old file for local changes and apply them to the new version.

7) Start PostgreSQL:
# rcctl start postgresql

8) Restore your data:
# su _postgresql -c "psql -U postgres < /var/postgresql/full.sqldump"

Option 2: pg_upgrade
--------------------

This will work for an upgrade from the previous major version of
PostgreSQL supported by OpenBSD to the current version, and should be
faster than a dump and reload, especially for large databases. 

1) Shutdown the server:
# rcctl stop postgresql

2) Upgrade your PostgreSQL package with pkg_add.
# pkg_add postgresql-pg_upgrade

3) Backup your old data directory:
# mv /var/postgresql/data /var/postgresql/data-${PREV_MAJOR}

4) Create a new data directory (using -E UTF8 if appropriate):
# su _postgresql -c "mkdir /var/postgresql/data"
# su _postgresql -c "initdb -D /var/postgresql/data -U postgres -A md5 -W"

5) Restore your old pg_hba.conf and (if used) SSL certificates
# su _postgresql -c \
    "cp /var/postgresql/data-${PREV_MAJOR}/pg_hba.conf /var/postgresql/data/"
# su _postgresql -c \
    "cp /var/postgresql/data-${PREV_MAJOR}/server.{crt,key} /var/postgresql/data/"

Some postgresql.conf settings changed or disappeared in this version.
Examine your old file for local changes and apply them to the new version.

6) Temporarily support connecting without a password for local users by
   editing pg_hba.conf to include "local all postgres trust"
# su _postgresql -c "vi /var/postgresql/data/pg_hba.conf"

7) Run pg_upgrade:
# su _postgresql -c "cd /var/postgresql && \
    pg_upgrade -b /usr/local/bin/postgresql-${PREV_MAJOR}/ -B /usr/local/bin \
    -U postgres -d /var/postgresql/data-${PREV_MAJOR}/ -D /var/postgresql/data"

8) Remove "local all postgres trust" line from pg_hba.conf
# su _postgresql -c "vi /var/postgresql/data/pg_hba.conf"

9) Start PostgreSQL:
# rcctl start postgresql

Clients/Frontends
=================
Many applications can use the PostgreSQL database right away.  To facilitate
administration of a PostgreSQL database, two clients are notable:

www/phppgadmin		A web based user interface that uses PHP5
databases/pgadmin3	A graphical user interface that uses wxWidgets
